1. Field of the Invention
This invention relates generally to the field of surgery. In particular, the present invention relates to the field of surgical access to the spine.
2. Background of the Invention
This invention relates generally to the field of devices, methodologies and systems involved in lumbar interbody fusion, wherein an interbody device or implant is positioned between adjacent vertebrae in order to stabilize or fuse the vertebrae. Modern surgical techniques for this are relatively minimally invasive, in that improved techniques, instrumentation and implant design allow the site to be prepared and the implant to be introduced through one or several small incisions in the patient.
Surgical procedures known as lumbar interbody fusion (LIF) have become common over the past ten years. Particular techniques are typically designated by the direction of approach relative to the spine—anterior (ALIF), posterior (PLIF), transverse (TLIF), and extreme lateral (XLIF). While these procedures are an improvement over conventional surgery in that muscular disruption and trauma are minimized, difficulties in the techniques have limited widespread adoption in the medical community.
For example, anterior approaches require the use of an access surgeon in addition to the spinal surgeon to navigate through the belly and require mobilization of the abdominal viscera and great vessels. Anterior approaches also do not safely allow for revision or re-exploration and can incur additional complication such as ileus and abdominal pain. Should further fixation be required these approaches do not allow posterior fixation without repositioning the patient; this procedure is commonly called a 360 operation where the operation begins with the patient in the supine position for the ALIF procedure and then flipped, re-sterilized and posterior fixation is applied with the patient in the prone position. These procedures increase time of operations which directly relates to blood loss, recovery time and hospital fees.
Posterior and transverse approaches require provide some advantages over anterior approaches yet still require some exposure of the nerves or theral sac, making placement of large (and therefore more stable) implants difficult; therefore posterior and transverse approaches use fixation devices smaller than anterior approaches.
Extreme lateral approaches still provide some advantages over previously discussed procedures yet require cumbersome positioning, long operating distances and provide no access to the spinal canal. In these approaches the patient is placed on their side which allows a larger access area to implant a bigger device but does not overcome the setback of repositioning the patient should posterior fixation be required.
It would be desirable to develop a posterior-lateral approach that combines the advantages of both the posterior and lateral approaches.